Manufacture of syntans from vanillin and leather tanned therewith



Patented Aug. 14,1951

MAN F CTU E OF SYNTANS; FROM VANIL:

LIN AND LEATHER TANNED THEREWITH John Miglarese, Cincinnati, Ohio, assignor to The United States Leather Company, New York, N. Y., a corporation of New Jersey No Drawing. Application September 8, 1948, Serial No. 48,322

i2 Claims. (01. 26049) My invention relates to a novel type of syntan made from vanillin and to the surprising results of the use of such syntan.

In the preparation of syntans it has been proposed to make a syntan by treating the concentrated sulphonation mixture (including unchanged sulphuric acid) of phenol sulphonic acid with formaldehyde at a temperature of 30 to 35 C. (Bureau of Standards Technological Papers,

vol. 20, No. 309, by Edward Wolensensky). Thus CHO Vanillin may be produced as a degradation produce of lignin.

An object of my invention is to utilize vanillin because its unique composition consisting of a phenolic group and an aldehyde group which are available to make a syntan, rich in phenolic groups, contribute surprisingly good leathering characteristics in tanning.

Another object of my invention is to make a leathering material practically in one step without the use of expensive equipment, merely by dissolving the phenol and vanillin and sulfonating, causing simultaneous sulfonation and condensation of the phenolic aldehyde and phenol, to a tanning material as follows:

Example 1 One mol of vanillin and two mols of phenol are dissolved in each other, and 1 mols of sulfuric acid (98%) is added with stirring in the course of 1 hour. Permit the temperature to rise of its own exothermic reaction. Stir for 1 /2 hours, add its weight of 5% lactic acid and neutralize the mass to a pH of 3.5 with sodium hydroxide which is ready for use in tanning.

Example 2 Condense 75.2 grams of phenol with 60.8 grams of vanillin (about 2 mols of phenol to 1 of vanillin) and 5 grams of oxalic acid for 3 hours, at the end of which produces a resinous masshaving a red color. 45-60 cc. of concentrated 98% H2804 is added to the mass gradually. The mass is made less viscous by a water bath to facilitate stirring. The H2804 is added in a period of /2 hour. The temperature is kept around -90 and the mixture is stirred for one hour at this temperature. The red mass is diluted with its weight of water. 20 grams of concentrated hydroxy acetic acid is added to the mass. The whole is made of pH of 3.5 with caustic soda or sodium carbonate. The synthetic tanning extract is now ready to be used for tanning. A piece of depickled skin is introduced into the liquor having 3% tanning content and the ratio of the liquor to the hide or skin is 5 to 1. The skin or hide is permitted to stand in liquor until the tanning material has struck through. The leather is oiled, dried and finished having full and excellent feel.

Example 3 The phenolic aldehyde, vanillin, can be used to condense 1 mol of phenol and 1 mol meta cresol in the presence of sulfuric acid performed the same way as in Example 1. The presence of cresol gives a brownish red colored tanning product and a brown leather. The skin is tanned as in Example 2.

Comparative tests on the skin tanned in accordance with Example No. 2 with skins tanned with other types of syntans and with vegetable tanning reagents indicate a quality of tanning heretofore unknown. There is a fullness and plumpness and soft feel which makes the skin tanned in accordance with my invention as set forth herein, stand out as different in physical properties than leathers tanned in other ways.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The method of producing a tanning material which comprises subjecting a mixture of a phenol and vanillin, in the proportions of about 2 mols of phenol to 1 of vanillin, to condensation and to sulfonation with concentrated sulfuric acid to form a water soluble condensation and sulfonated product and reducing the acidity of the resulting product to a pH of around 3.5.

2. A synthetic tanning material produced in Number Name Date accordance with the process of claim 1. 1,539,517 Schmidt May 26, 1925 JOHN MIGLARESE. 1,679,322 McIntosh July 31, 1928 2,040,212 Orthner May '12, 1936 REFERENCES CITED 5 2,099,717 Alles NOV. 23, 1937 The following references are of record in the 211221124 A1195 June 1938 file of this patent: 32 3 g2 a e ec.

UNITED STATES PATENTS 2,186,509 Wallace Jan. 29, 1940 Number Name Date 10 2,191,737 Alles Feb. 27, 1940 

1. THE METHOD OF PRODUCING A TANNING MATERIAL WHICH COMPRISES SUBJECTING A MIXTURE OF A PHENOL AND VANILLIN, IN THE PROPORTIONS OF ABOUT 2 MOLS OF PHENOL TO 1 OF VANILLIN, TO CONDENSATION AND TO SULFONATION WITH CONCENTRATED SULFURIC ACID TO FORM A WATER SOLUBLE CONDENSATION AND SULFONATED PRODUCT AND REDUCING THE ACIDITY OF THE RESULTING PRODUCT TO A PH OF AROUND 3.5. 